Integrated Metabolo-transcriptomics Reveals the Defense Response of Homogentisic Acid in Wheat against Puccinia striiformis f. sp. tritici

Abstract

Stripe rust is a widespread and harmful wheat disease caused by Puccinia striiformis f. sp. tritici (Pst) worldwide. Targeted metabolome and transcriptomics analyses of CYR23 infected leaves were performed to identify the differential metabolites and differentially expressed genes related to wheat disease resistance. We observed upregulation of 33 metabolites involved in the primary and secondary metabolism, especially for homogentisic acid (HGA), p-coumaroylagmatine, and saccharopine. These three metabolites were mainly involved in the phenylpropanoid metabolic pathway, hydroxycinnamic acid amides pathway, and saccharopine pathway. Combined with transcriptome data on non-compatible interaction, the synthesis-related genes of these three differential metabolites were all upregulated significantly. The gene regulatory network involved in response to Pst infection was constructed, which revealed that several transcription factor families including WRKYs, MYBs, and bZIPs were identified as potentially hubs in wheat resistance response against Pst. An in vitro test showed that HGA effectively inhibited the germination of stripe rust fungus urediniospores and reduced the occurrence of wheat stripe rust. The results of gene silencing and overexpression of HGA synthesis-related gene 4-hydroxyphenylpyruvate dioxygenase proved that HGA was involved in wheat disease resistance. These results provided a further understanding of the disease resistance of wheat and indicated that HGA can be developed as a potential agent against Pst.

The Role of Hydroxycinnamic Acid Amide Pathway in Plant Immunity

“…HCAAs synthesized as a result of F. graminearum infection were observed regardless of susceptibility, but occurred at different times after infection ( Whitney et al, 2022 ). In the incompatible interaction between wheat and stripe rust, the HCAAs pathway was strongly induced, and p -coumaroyl agmatine was significantly increased ( Liu et al, 2022 ). Significantly increased levels of sinapic acid and ferulic acid in wheat after infestation with stripe rust ( Atta et al, 2020 ).…”

LysM Proteins TaCEBiP and TaLYK5 are Involved in Immune Responses Mediated by Chitin Coreceptor TaCERK1 in Wheat

“…Primer design and reactions were conducted as described previously . The primers for qRT-PCR are shown in Table S2.…”

“…Primer design and reactions were conducted as described previously. 32 The primers for qRT-PCR are shown in Table S2. Gene profile analysis was quantified using a CFX96 real-time PCR detection system (Bio-Rad).…”

Leaf rust (Puccinia recondita f. sp. secalis) triggers substantial changes in rye (Secale cereale L.) at the transcriptome and metabolome levels

“…In addition to alterations at the transcriptome level, plant immune responses also involve the synthesis of immunity-related metabolites [ 20 ]. Phenylpropanoids and their downstream metabolites (flavonoids) are scavengers of reactive oxygen species (ROS) generated in response to environmental stresses [ 20 , 21 ]. Moreover, several phenolics and the glycosidic forms of flavonols are inhibitors of fungal growth in cereals [ 22 , 23 ].…”

“…The thoroughly characterized diterpenes involved in rice–pathogen interactions are momilactones and oryzalexins [ 27 , 28 ]. Moreover, biogenic amines and their phenol-containing conjugates accumulate rapidly during the interaction between pathogens and plants, including rye [ 29 ], barley [ 30 ], and wheat [ 21 ].…”